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-   -   Differences in Q-jet vs 585 Holley vs 4GC (https://classracer.com/classforum/showthread.php?t=60464)

JP Schuster 12-08-2015 03:29 PM

Differences in Q-jet vs 585 Holley vs 4GC
 
Anyone ever tried them on the same motor and noted the ET or HP differences?

tj310 12-09-2015 10:47 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
I have run the 327 in SS trim that uses 4gc or Q-jet and found the difference is accurately reflected in the HP factors. My motor is low budget.
I spoke to a racer who uses the 327 back and forth between the Holley and Q-jet he claimed Holley was a little quicker . ---Trevor

Mike Taylor 3601 12-10-2015 10:31 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Only comparison I have is I test my Q-jet against 850 dbl. pump holley,just out the box carb on my 305 dynoed pretty much same all the way through the pull,holley made 3lbs more tq. @ peak tq..
Then later had a 351C 4bbl head street/strip engine put my q- jet on it and got same results as the 305 identical except about 3lbs. tq. difference @ peak tq.
Not really what you asked but maybe help some how.
Mike Taylor 3601

Dan Fahey 12-10-2015 12:13 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by tj310 (Post 489826)
I have run the 327 in SS trim that uses 4gc or Q-jet and found the difference is accurately reflected in the HP factors. My motor is low budget.
I spoke to a racer who uses the 327 back and forth between the Holley and Q-jet he claimed Holley was a little quicker . ---Trevor

I had one of my Qjets reworked by Val Headworth.
It was flow tested and had new Air Bleeds and new parts.
It ran a little better than the ones I reworked.
Just felt better, crisper, no bogging.

Dan

Supershifter55 12-11-2015 02:34 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
What is the"585 Holley" and what combination did it come on?

Thanks, Gary Howe,

JP Schuster 12-11-2015 03:04 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
585 CFM Holley and I believe it was on 327 in Corvette's for a few years in the 60's. I'm not sure of the exact details because I have never ran this before. Just word of mouth.

Dragsinger 12-11-2015 03:17 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
The "585" Holley was on a 1966 Corvette 327/300. Quick Fuel builds a legal replacement #VS585R

I have it on my Super 10

Jeff Jewell 12-11-2015 05:01 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by Supershifter55 (Post 489985)
What is the"585 Holley" and what combination did it come on?

Thanks, Gary Howe,

The 585 was also on the 427/390 engine in 66 and 67 Corvettes. Way too small for a 427...

Ernie Neal 12-12-2015 12:41 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
The 585 was used on the Corvette 327/300 66/67 a 585 was also used on the 350hp engine in 65/66 it had jet plates on both ends. The carb we are talking about has 1 9/16" throttle plates. Don't confuse this carburetor with the 66 chevy II and others with 275 hp and a holley it only has 1 1/2" plates.

We use the 67 327/300 comb in the Sunfire my son drives. In our case the holley is better due to the hp factor, but may not work as well in all cases.

Ernie Neal
SS 354

Mark Yacavone 12-12-2015 01:19 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by Ernie Neal (Post 490021)
The 585 was used on the Corvette 327/300 66/67 a 585 was also used on the 350hp engine in 65/66 it had jet plates on both ends. The carb we are talking about has 1 9/16" throttle plates. Don't confuse this carburetor with the 66 chevy II and others with 275 hp and a holley it only has 1 1/2" plates.

We use the 67 327/300 comb in the Sunfire my son drives. In our case the holley is better due to the hp factor, but may not work as well in all cases.

Ernie Neal
SS 354

Yes, the 66 540 Holley should be rated about five more than the 4GC, but so far, NHRA doesn't want to hear about it.

james schaechter 12-12-2015 09:18 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by Mark Yacavone (Post 490024)
Yes, the 66 540 Holley should be rated about five more than the 4GC, but so far, NHRA doesn't want to hear about it.

Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)

impstocker 12-12-2015 10:51 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
With my 65 Impala build, I am able to use a 585 Holley on my 396/325 (410 CI now)I do have one to use, just need to find a manifold. I always feel more comfortable with Holleys too, opinions vs Q-Jet. I will probaly try both anyway.

Will Lamprecht I/SA 65 Impala looking to 2016 season.

impstocker 12-12-2015 10:56 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Just a thought, maybe better fuel distribution through the manifold with the Holley vs the spread bore Q-Jet even though more CFM with Q-Jet?

Will Lamprecht -

Mark Yacavone 12-12-2015 01:35 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by james schaechter (Post 490028)
Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)

Yes ,I know all about that deal.
Joe Sr. and I raced a 66 Chevy II way back when you had to use the Holley or Carter , and not the Q jet.
Still possibly the fastest SS/J car in the country at the end of 1973..Record holder, and No. 1 qualifier at the World Finals in Amarillo...with the 540 Holley.
You could use a Q Jet on a 67. This is the reason ,I believe , that Larry Tores built the 67 post car.
Anyway, I think we were talking about SS/GT here.
Don't you think the small Holley should be rated less than the big one, or the Carter, for that matter?
Also nobody has mentioned the little Corvette WCFB yet, on the 520 head combos

nhramnl 04-04-2016 10:20 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by james schaechter (Post 490028)
Mark, that little carb option is still rated at 274 on our car. 66 nova stickshift. I have heard from a couple racers (not in Midwest) that said the 585 was a legal replacement on the stocker 327 275 but I really really doubt that is legit. We run the QJet on that combo in stock and it works well. ( and UH OH! we actually have the product engineering bypass regulator on our car as well)


And let me guess; the car is quicker, but only because you're carrying less weight down the track, with that lighter wallet!

Joe Schaechter 04-07-2016 07:00 PM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Quote:

Originally Posted by nhramnl (Post 500096)
And let me guess; the car is quicker, but only because you're carrying less weight down the track, with that lighter wallet!

I like it on our car with the Qjet. When we were running the 4GC and Holley carb combinations it was never a problem with our old fuel system. We found those two carbs are more forgiving. The Qjet was harder to get consistent performance prior to adding the Product Engineering bypass. Everyone has their own approach to make their car work and opinions are going to vary on where to spend their money.

http://i303.photobucket.com/albums/n...ps7a6c0c73.jpg

dmir55 04-10-2016 10:10 AM

Re: Differences in Q-jet vs 585 Holley vs 4GC
 
Holleys are easier to change the boosters on. Just a thought.


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